In a glass melting furnace, molten glass is produced by heating a glass raw material in a powder or particle form with a burner flame or the like. This molten glass is formed into various glass products through predetermined forming steps such as pressing and blowing.
In this case, emission gas generated from the glass melting furnace contains a part of components of the glass raw material in a gaseous or small-sized solid form. Therefore, the emission gas also contains a great amount of components which can be recycled as a glass raw material. Thus, the recovery of a recycle feed from the emission gas can also contribute to saving of a glass raw material. Further, environment can be simultaneously taken into consideration.
However, when an attempt is made to recover a recycle feed from the emission gas, the recycle feed contains a great amount of components which has an adverse effect on the quality of glass due to fuel for a burner flame and impurities contained in the glass raw material. Therefore, it is actually difficult to use a recycle feed recovered from emission gas as a glass raw material. Herein, as the impurities which have an adverse effect on the quality of glass, for example, there are given a hydrosulfate and a halide, and the hydrosulfate causes the generation of air bubbles in glass.
For example, in Patent Literature 1, there is disclosed a method of reducing a sulfur oxide which causes air bubbles from the emission gas and recovering a recycle feed which can be utilized as a glass raw material by using fuel not substantially containing a sulfur component as fuel for a burner flame and using a material whose content of a sulfur component is also small correspondingly as a glass raw material.